The present application is the U.S. national phase under 35 U.S.C. 371 of International Application No. PCT/DE99/01574 filed May 28, 1999 claiming priority of German Patent Application No. 198 27 175.1 filed Jun. 18, 1998.
1. Field of the Invention
The invention relates to an analyzer plug-in unit for a polarization microscope. The analyzer insert is of the type having a support that can be inserted into the optical path of the microscope, an externally positioned adjusting wheel that can be manipulated by hand, and adjacent thereto, in the direction of insertion, an internally positioned analyzer that is mounted on a rotating analyzer mount so the analyzer can be inserted into the optical path of the microscope, and transmission means for transmitting the rotating motion of the adjusting wheel to the analyzer mount and analyzer.
2. Description of the Related Art
DE-GM 69 22 326 describes an analyzer for a polarization microscope, in which there are mounted on a support that can be inserted into the microscope""s optical path an adjusting wheel that is manually operated and is externally positioned, as well as an internally positioned analyzer adjacent thereto in the direction of insertion, on a analyzer mount that is able to rotate. A geared combination consisting of a screw on the adjusting wheel and a gear ring on the analyzer mount serve to transmit the rotating motion of the adjusting wheel to the analyzer. The disadvantage of this design rests in the fact that gears with gearwheels are very expensive and in that the scale needed for installing the analyzer insert is necessarily large.
DE-AS 12 78 134 describes an interference accessory for a polarization microscope with a crystal plate positioned on a support. The latter can be moved perpendicular to the microscope""s optical path by means of a push-rod and can be brought into defined locking positions by means of interlocking devices. Positioning between the locking positions and the rotation of the crystal plate is not possible. Furthermore, the push-rod and the locking device require much space.
The goal of this invention is to create a cost-effective analyzer insert of slight height which gives the analyzer an adjusting range of 180xc2x0 and which permits precise and slip-free adjustment.
In the analyzer insert according to the invention the rotating motion of the adjusting wheel is transmitted to the rotating analyzer by two equally long adjusting levers that run parallel to each other. To this end, the ends of the adjusting lever on the adjusting wheel and the other ends on the analyzer mount are mounted in rotating fashion, in each case on bearing axles close to the rim. The bearing axles are positioned in such a way that they produce force levers on the adjusting wheel and on analyzer mount that are of equal length with respect to their rotating axes and which lie at a 90xc2x0 angle to each other.
In the initial position, corresponding to the 0xc2x0 position, all four bearing axles lie on a straight line. In order to make this possible, one adjusting lever can be positioned at a higher level than the other. As a result, the adjusting levers can partly lie one above the other in the initial position. Another possibility is to design the adjusting levers with angled ends. In this way the four bearing axles will lie on a straight line, even when the two adjusting levers are mounted at the same height. In addition, the adjusting levers may exhibit recesses which prevent them from striking against the bearing axles of the other levers.
Rotating the adjusting wheel will cause the bearing axles to further turn both on the adjusting wheel and on the analyzer mount and the two adjusting levers to be brought to a wider distance apart. In the 90xc2x0 position the separating distance is greatest, and they are symmetrically positioned at either side of the connecting line that is formed by the rotating axes of the adjusting wheel and the analyzer. Upon further rotation, the distance between the adjusting levers lessens, until the four bearing points again lie on a straight line in the 180xc2x0 position, in a position opposite the starting position. In this position also it proves to be advantageous if the adjusting levers and their position is like that already described for the 0xc2x0 position.
The use of two adjusting levers in the described configuration permits a uniform and precise rotating motion between 0xc2x0 and 180xc2x0 and a dead point is avoided upon rotation of the adjusting wheel and the translation of force.
The adjusting wheel must turn in the right direction in order for the adjusting levers not to overlap the analyzer area and overshadow the optical path of the microscope. This is accomplished with markings or stops that prevent rotation beyond the 0xc2x0 or the 180xc2x0 position.
To this end, the bearing axles on the adjusting wheel and/or the analyzer mount can be advantageously applied to the same area. The adjusting levers positioned on the same surface then enter the xe2x80x9cterminal positionsxe2x80x9d 0xc2x0 and the 180xc2x0, run against the other bearing axle, and cease to rotate. To permit a particularly flat design, the adjusting levers can be manufactured out of thin sheets of metal. These might be subject to bending when the adjusting levers run against each other. To prevent this, the analyzer insert will ideally be provided with overrun protection. To this end, two protruding pins, corresponding to the 0xc2x0 or 180xc2x0 position of the analyzer, are mounted on the adjusting wheel. A stop screw is positioned on the support in the swivel range of these pins, and the pins will strike the screw in the 0xc2x0 or 180xc2x0 position of the analyzer. Overrun of the given positions is thereby prevented.
The adjusting levers can be economically produced from identical thin metal sheets. Simple metal pins can be used as bearing axles. Boreholes can be applied to the ends of the metal strips; the diameter of these boreholes is only slightly larger than the diameter of the pins. The adjusting levers can thus turn freely around the bearing pins.
Thus, the analyzer insert according to the invention can be realized simply and with economical components and is considerably more cost-effective than known analyzer inserts with gearwheels or transmission belts. In addition, the problem of slippage that arises with this prior art does exist in the present invention, since the force is transmitted directly with the rigid adjusting levers.